DNA barcoding of selected UAE medicinal plant species: a comparative assessment of herbarium and fresh samples

It is commonly difficult to extract and amplify DNA from herbarium samples as they are old and preserved using different compounds. In addition, such samples are subjected to the accumulation of intrinsically produced plant substances over long periods (up to hundreds of years). DNA extraction from desert flora may pause added difficulties as many contain high levels of secondary metabolites. Herbarium samples from the Biology Department (UAE University) plant collection and fresh plant samples, collected from around Al-Ain (UAE), were used in this study. The three barcode loci for the coding genes matK, rbcL and rpoC1-were amplified. Our results showed that T. terresteris, H. robustum,T. pentandrus and Z. qatarense were amplified using all three primers for both fresh and herbaium samples. Both fresh and herbarium samples of C. comosum, however, were not amplified at all, using the three primers. Herbarium samples from A. javanica, C. imbricatum, T. aucherana and Z. simplex were not amplified with any of the three primers. For fresh samples 90, 90 and 80% of the samples were amplified using matK, rbcL and rpoC1, respectively. In short, fresh samples were significantly better amplified than those from herbarium sources, using the three primers. Both fresh and herbarium samples from one species (C. comosum), however, were not successfully amplified. It is also concluded that the rbcL regions showed real potentials to distinguish the UAE species under investigation into the appropriate family and genus.     

Potential risk of biologic pollution associated to the introduction of <i>Pinus radiata</i> in grassland areas

Afforestation is a recommended practice to mitigate global warming. However, their implementation may generate undesirable impacts, mostly if exotic species are used. Plantations of Pinus radiata D Don in Ventania (Bs. As., Argentina) soils showed notorious increments of extractable P (Pe), which could affect the dynamic of this element as well as the degree of phosphorus saturation (GSP_Bray). The objectives of this study were: i) to quantify the GSP_Bray in Mollisols afforested with P. radiata comparing the results with those coming from adjacent, natural grassland areas (base line); ii) to evaluate the potential environmental risk induced by afforestation through the identification of a change point (PC) in the GSP_Bray indicative of a phosphate leaching increment. Treatments included mature stands of P. radiata (TB) and adjacent areas with natural grassland vegetation (TP). Samples were taken at 0-15; 15-30 and 30-45 cm soil depth, and texture, pH, total organic carbon (COT), Pe, soluble reactive phosphorus (PSR), phosphorus sorption index (ISP) and GSP_Bray were determined. The results showed a significant acidification in TB and an increase in the COT stock, indicating an additional atmospheric CO₂ sequestration by the trees. The Pe and PSR values were notoriously higher in TB, and they were reflected in a significant increment in the GSP_Bray with respect to TP. The detection of a significant PC in the GSP_Bray-PSR regression indicates higher chances of phosphate leaching in the forest stands, which could reach water courses, lakes and artificial reservoirs promoting their eutrophication. Because of the potential environmental pollution risk of biologic origin derived from the afforestation with P. radiata in Mollisols areas, their inclusion in clean development practices must be reconsidered.     

Impacts of nanoparticles and phosphonates in the behavior and oxidative status of the mediterranean mussels (Mytilus galloprovincialis)

The current study investigated the exposure of the Mediterranean mussel (Mytilus galloprovincialis) to gold nanoparticles decorated zinc oxide (Au-ZnO NPs) and phosphonate [Diethyl (3-cyano-1-hydroxy-1-phenyl-2-methylpropyl)] phosphate (PC). The mussels were exposed to concentrations of 50 and 100 µg L^-1 of both compounds alone, as well as to a mixture of both pollutants (i.e. Mix). The singular and the combined effect of each pollutant was investigated by measuring the concentration of various metals (i.e., Cu, Fe, Mn, Zn and Au) in the the digestive glands and gills of mussels, their filtration capacity (FC), respiration rate (RR) and the response of oxidative biomarkers, respectively, following 14 days of exposure. The concentrations of Cu, Fe, Mn, Zn and Au increased directly with Au-ZnO NPs in mussel tissues, but significantly only for Zn. In contrast, the mixture of Au-ZnO100 NPs and PC100 did not induce any significant increase in the content of metals in digetsve glands and gills, suggesting antagonistic interactions between contaminants. In addition, FC and RR levels decreased following exposure to Au-ZnO100 NPs and PC100 treatments and no significant alterations were observed after the exposure to 50 µg.L^-1 of both contaminants and Mix. Hydrogen peroxide (H₂O₂) level, GSH/GSSG ratio, superoxide dismutase (SOD), catalase (CAT) and acetylcholinesterase (AChE) activities showed significant changes following the exposure to both Au-ZnO NPs and PC, in the gills and the digestive glands of the mussel. However, no significant modifications were observed in both organs following the exposure to Mix. The current study advances the understanding of the toxicity of NPs and phosphonates on M. galloprovincialis and sets the path for future ecotoxicological studies regarding the synergic effects of these substances on marine species. Moreover, the current experiment suggests that the oxidative stress and the neurotoxic pathways are responsive following the exposure of marine invertebrates to both nanoparticles and phosphonates, with potential antagonist interactions of these substances on the physiology of targeted species.     

Rôle of phagostimulants of cotton leaves in the feeding behaviour of Spodoptera littoralis

Petroleum ether extract of cotton leaves was the most attractive to the hatched larvae of Spodoptera littoralis, and it remained so even after removal of the chlorophyll and other pigments. Steam distillation of this filtrate gave a volatile oil which also proved highly attractive to the larvae. In this fraction, 12 components were identified by thin-layer chromatography. Of these components, α-terpineol, citronellol and α-pinene were the most attractive, whereas humulene and linalool were less attractive. The remaining non-volatile lipid fraction was also attractive to the larva. In this fraction the unsaponifiable matter contained the attractive ingredients. This fraction proved to be a hydrocarbon. The infrared spectrum and nuclear magnetic resonance showed only typical hydrocarbon bonds.     

Macrocyclic diterpene esters from Euphorbia royleana

An ether soluble resin was prepared by extraction and partition of the latex of Euphorbia royleana. This resin demonstrated pronounced pro-inflammatory activity on mammalian skin and was separated into biologically active and inactive fractions by dry column chromatography. The inactive fraction was further separated by adsorption and partition thin-layer methods. The least polar zone consisted of an inseparable mixture of four tetra-esters of the macrocyclic diterpene ingol, whilst the more polar fraction consisted of a mixture of four tri-esters of the same diterpene.     

Streptococcal antigen I/II binds to extracellular proteins through intermolecular beta-sheets

One of the functions associated with the oral streptococcal surface protein I/II is to bind to human extracellular matrix molecules or blood components, which could act as opportunistic ligands in pathological circumstances. In order to understand the relative specificity of the binding repertoire of this bacterial adhesin, we examined by infrared measurements the mode of binding of the protein I/II from Streptococcus mutans OMZ175 (I/IIf) to fibronectin and fibrinogen. This approach revealed the beta-structure forming capacity of I/IIf upon interaction with both proteins. The forming of intermolecular beta-structures may provide a non-selective way of interaction between I/IIf and its possible targets.     

The roles of the hybrid cluster protein,Hcp and its reductase,Hcr, in high affinity nitric oxide reduction that protects anaerobic cultures of Escherichia coli against nitrosative stress

The hybrid cluster protein, Hcp, contains a 4Fe‐2S‐2O iron‐sulfur‐oxygen cluster that is currently considered to be unique in biology. It protects various bacteria from nitrosative stress, but the mechanism is unknown. We demonstrate that the Escherichia coli Hcp is a high affinity nitric oxide (NO) reductase that is the major enzyme for reducing NO stoichiometrically to N₂O under physiologically relevant conditions. Deletion of hcp results in extreme sensitivity to NO during anaerobic growth and inactivation of the iron‐sulfur proteins, aconitase and fumarase, by accumulated cytoplasmic NO. Site directed mutagenesis revealed an essential role in NO reduction for the conserved glutamate 492 that coordinates the hybrid cluster. The second gene of the hcp‐hcr operon encodes an NADH‐dependent reductase, Hcr. Tight interaction between Hcp and Hcr was demonstrated. Although Hcp and Hcr purified individually were inactive or when recombined, a co‐purified preparation reduced NO in vitro with a Km for NO of 500 nM. In an hcr mutant, Hcp is reversibly inactivated by NO concentrations above 200 nM, indicating that Hcr protects Hcp from nitrosylation by its substrate, NO.     

Association between SIRT1 Gene Polymorphisms and Breast Cancer in Egyptians

Background

Breast cancer is reported to cause the highest mortality among female cancer patients. Previous studies have explored the association of silent mating-type information regulator 2 homolog 1 (SIRT1) gene expression with prognosis in breast cancer. However, no studies exist, so far, on the role of SIRT1 gene polymorphism in breast cancer risk or prognosis. The present study aimed to assess the association between SIRT1 gene polymorphisms and breast cancer in Egyptians.

Methods

The study comprised 980 Egyptian females divided into a breast cancer group (541 patients) and a healthy control group (439 subjects). SIRT1 gene single nucleotide polymorphisms (SNPs) rs3758391, rs3740051 and rs12778366 were genotyped using real-time polymerase chain reaction (RT-PCR). Allelic and genotypic frequencies were determined in both groups and association with breast cancer and clinicopathological characteristics was assessed.

Results

Breast cancer patients exhibited elevated serum SIRT1 levels which varied among different tumor grades. SIRT1 rs3758391 and rs12778366 TT genotypes were more frequent, exhibited higher SIRT1 levels than CC and CT genotypes and were associated with histologic grade and lymph node status. SIRT1 rs12778366 TT genotype also correlated with negative estrogen receptor (ER) and progesterone receptor (PR) statuses. The T allele frequency for both SNPs was higher in breast cancer patients than in normal subjects. Combined GG and AG genotypes of rs3740051 were more frequent, showed higher serum SIRT1 levels than the AA genotype, and were associated with ER and PR expression. Furthermore, inheritance of the G allele was associated with breast cancer.

Conclusions

Our findings reveal that rs3758391 and rs12778366 polymorphisms of SIRT1 gene are associated with breast cancer risk and prognosis in the Egyptian population.